Mirror Heating

From 6/90 a PTC Heating System has been used. Previously, the heating element circuit used a thermo-switch to turn the current ON if the glass temperature fell below 5~C (41~F) and OFF if it exceeded 50~C (120~F). This system resulted in a large spread of tolerances complicating fault diagnosis. With PTC heating, the resistance of the heating circuit changes depending on the temperature. The heating is never completely turned off, resulting in a constant current draw of 0.9-1.0 Amp. per mirror with the ignition switch ON.

The coloring on the backside of the mirrors has no meaning. A green dot on the mirror glass identifies it as a service (replacement) part.

The E32 will continue to use the thermo-switch system until the introduction of a new outside mirror in early 1991.